Machine for developing blueprints



June 23, 1942. H. J. BRUNK I MACHINE FOR DEVELOPING BLUE PRINTS Original Filed Jan. 21, 1959 INVENT OR. Q/omwv; @W JW y @www 'Q4/@0.

Patented lJune 23, 1942 MACHINE FOR DEVELOPING BLUEPRINTS Harold J. Brunk, Chicago, Ill., assignor to The C.

F. Pease Company, a corporation oi' Dela- Ware Original application January 21, 1939, Serial No. 252,203, which is a division of application Serial No. 11,142, March 14, 1935. Divided and this application January 31, 1941, Serial No. 376,869

(ci. sas-75j 8 Claims.

My invention relates to improvements in apparatus for making photographic prints, i. e. prints made by exposing to light` a sheet of paper or other suitable membrane having light sensitive chemicals applied thereto. Blue prints are included among those falling within the scope of the invention. In developing such prints water is used resulting in so-called bleeding, i. e. discoloration of the white areas by the blue coloring material.

The general object of the invention is to provide new and simple means for overcoming the diiiiculties due to running and bleeding heretofore inherent in the use of liquid in developing photo-copies or prints.

This application is a division of my copending application Serial No. 252,203, led January 21, 1939, now Patent No. 2,234,796, issued March 1l, 1941, which in turn is a division of my application Serial No. 11,142, filed March 14, 1935, now Patent No. 2,145,752, issued January 31, 1989.

More specically, the object of the present invention is to provide means for applying moisture to the exposed or coated surface of the paper by means of a dampened, absorbent material brought in contact with said surface but with no slippage.

The eiect is that of blotting a sensitized surface with moist, absorbent material after exposure to light, to withdraw the chemicals which it is desired to remove from the coated surface and to supply the necessary liquid. Thereafter, in the case of a blue print for example, it will be found that the unexposed areas are white or practically free from the unreduced chemical and that the exposed portion of the print shows that not only the loose outer layer of ferrous compound has been removed but oxidation has started sufficiently to prevent bleeding or running of the color when the print is subjected to the regular treatment with running water or a water bath.

In the accompanying drawing I have illustrated two embodiments of the invention in the form of attachments to well known types of so-called continuous blue printing machines. The invention may be embodied in other forms, however, and used in fields other than photography.

Fig. 1 is a side elevation of part of a blue printing machine, combined with one form of attachment; and

Fig. 2 is a side elevation of a modified form of the invention.

The machine shown in Fig. 1 comprises a suitable frame I0, having a supply of blue print paper in the form of a roll (not shown) mounted near the front of the machine. The paper is drawn rearwardly over a horizontal portion or table II, in the form of a long span I2, and thence upwardly past a curved sheet of glass I3, pasta row of arc lamps I4, or other suitable source of light. Said paper then passes over rollers I5, I6 and down under tension roller I1, the shaft I8v of the latter being mounted in suitable, vertically adjustable bearings, not shown, which, however, are supported on a chain I9 whereby the paper is maintained under the proper tension. From the tension roller the paper passes over` the roller 20, down under rollers 2I and 22, upwardly and over roller 23 near the top of the frame of the attachment and thence downwardly around larger roller 24 which is mounted on a suitable shaft 25.

The material for accomplishing the blotting or absorbing action is, in this case, a moist, endless belt 26 of suitable material such as felt, which belt passes around rollers 2128, mounted near the main roller 24, said belt passing downwardly around rollers 29 and 30, which latter are mount ed in a container or tank 3|. The roller 29 is mounted on a pivoted arm 32 provided with a spring 33 which maintains suitable tension on the endless belt. The latter, it will be seen, is caused to bear against the coated side of the sheet of blue print paper I2 where it passes around the roller 24 and is held in firm Contact therewith, without slippage, for more than half of the circumference of said roller. The length of the path of travel of the absorbent belt while it is in contact with the blue print, may be varied by adjusting the arm 34 on which the roller 28 is mounted, said arm being mounted to swing about the axis of the shaft 25. The span of paper has its coated side I2 uppermost as it leaves the printer and passes under the tension roller Il, one of the purposes of the additional rollers between said tension roller and the main roller 24 being to turn the paper upside down during its travel so that its coated surface may be brought into contact with the absorbent belt as both spans pass around said main roller.

It is necessary to wash from the absorbent belt the chemicals which adhere thereto while it is in contact with the exposed surface of the blue print paper, and for this purpose said belt is passed through a water bath in the tank 3|. The descending span is Washed with water by means of a spray issuing from the pipe 35, the water being applied to the Aside of the belt which was in contact with the blue print. This tends to wash the chemicals from the belt, which washing is further accomplished as the latter passes through the water bath in the tank, the level of the water being maintained by a suitable overflow pipe 36. If desired, a revolving brush or brushes such as 31 may also be employed to aid in removing any surplus chemical from the belt. If the chemical were not removed it would, of course, be brought into contact with the surface of the print during the contnued travel of the endless belt around the main roller and would stain the blue print, due to the chemical reaction which would takel place.

After the blue print paper leaves the main roller 24, it passes through a conventional water Wash, indicated at 38, but Without any bleeding or running of the color and is thereafter nxed and dried in any suitable manner.

Inl Fig. 2 a modification of the means for pressn ing the absorbent material against the span of blue print paper is illustrated. In the attachment just described the paper passes around a roller with its coated and exposed side outwardly, an endless belt of absorbent material being pressed against said coated side, and caused to travel with the blue print paper. In the modied form of the device, the moist, absorbent material forms an outer layer on a -roller and the coated side of the paper passes over the roller facing inwardly instead of outwardly, and hence is in cony moistened by a blotting action.

a container for water having a roller therein, three adjacent rollers above said container and an endless band of absorbent material passing under said roller in said container and back and forth around said three upper rollers, one of said three rollers being adjustable with reference to another roller whereby the circumferential travel of said band around said other roller may be varied, and additional rollers for directing the sheet of blue print paper around said vother rollerl with its coated side in .contact withsaid endless belt of absorbent material, whereby said band is 4. A machine as in claim 3 with of means for washing said endless belt to free the same from any chemicals removed from said band.

5. A machine for developing blue prints and the like, comprising an endless band of absorbent material, means for supporting and directing said absorbent material along an endless path of travel, a flexible band of fibrous material coated with blue print chemicals on one face thereof, means for moving said ilexible band into intimate contact with the coated face of said absorbent material so that the two travel together without roller receives in turning with its lower part submerged in the water bath.

The operation described in connection with the apparatus of Figs. 1 and 2 might be called a mechanical method of applying moisture to the surface of a blue print and removing. the loose, exposed chemical as well as the underexposed chemical therefrom and without the possibility of any migration of the blues into the whites.

Various changes may be made in the structural features and in the combinations of elements described, without departing from the spirit of the invention as expressed in the appended claims.

I claim:

l. A blue print machine'comprising a printing station and a washing station and means for feeding a band of blue printV paper past said stations with its sensitized side exposed thereto, and an intermediate moisture applying station comprising an endless belt of absorbent material, a water tank into which said belt dips while traveling and means for pressing the coated side of said blue print paper against said endless belt above the water level whereby said blue print paper is moistened insuillciently to cause discoloration of the white areas.

' 2.\A blue print machine comprising a printing station and a washing station and means for feeding a band of blue print paper past said stations with its sensitized side exposed, and an intermediate moisture-applying station comprising a tank having water therein, rollers in said tank and above said tank, an endless belt of absorbent material passing around said rollers. saidtlue print paper also passing around one of said rollers with its coated side in contact with said endless belt to moisten said paper without washing the chemical coating therefrom.

3. A blue print machine comprising a printing station and a washing station and means for feeding a band of blue print paper past said stations with its sensitized side exposed, and an intermediate moisture-applying station comprising slipping one over the other, and means for applying water evenly to said absorbent material at points remote from the area of contact of said bands, whereby part of said water is transferred evenly from said absorbent band to said chemical coating and in amounts insufficient to supersaturate said iibrous material.

6. A machine for developing blue prints comprising a tank for liquid developer, a roller below the level of the liquid in said tank, a roller above said level, a belt of absorbent material passing over said rollers whereby it is moistened byv said liquid, and an additional roller adjacent the path of travel of said belt over which a band of blue print paper travels with its coated face pressed against said belt to receive moisture from said belt without relative movement between said coated face and said moist belt.

'7. A machine for developing blue prints comprising a tank for liquid developen'a roller below the level of the liquid in said tank, a roller above said level, Va belt of absorbent material passing jover said rollers whereby it is moistened by said liquid, an additional-roller adjacent the path. of travel of said belt overvwhich a band of blue print paper travels with its coated face pressed against said belt to receive moisture from said belt without relative movement between said coated face and said moist belt, and a brush mounted in said tank in engagement with said belt to ald in removing therefrom any coating transferred thereto from said blue print paper.

8. A machine for developing blue prints comprising a tank for liquid developer. a roller below the level of the liquid in said tank,- aroller above said level, a belt of' absorbent material passing over said rollers whereby it is moistened by said liquid, an additional roller adjacent the path of travel of said belt over which a band of blue print HAROLD J. BRUNK. I

the addition 

